Skip to main content

Full text of "IS 2911-1-1: DESIGN AND CONSTRUCTION OF PILE FOUNDATIONS — CODE OF PRACTICE, Part 1: CONCRETE PILES, Section 1: Driven Cast In-situ Concrete Piles"

See other formats


**************** 



^ tOTH: 




Disclosure to Promote the Right To Information 

Whereas the Parliament of India has set out to provide a practical regime of right to 
information for citizens to secure access to information under the control of public authorities, 
in order to promote transparency and accountability in the working of every public authority, 
and whereas the attached publication of the Bureau of Indian Standards is of particular interest 
to the public, particularly disadvantaged communities and those engaged in the pursuit of 
education and knowledge, the attached public safety standard is made available to promote the 
timely dissemination of this information in an accurate manner to the public. 



Mazdoor Kisan Shakti Sangathan 
"The Right to Information, The Right to Live" 



Jawaharlal Nehru 
"Step Out From the Old to the New" ' 



IS 2911-1-1 (2010) : DESIGN AND CONSTRUCTION OF PILE 
FOUNDATIONS - CODE OF PRACTICE, Part 1: CONCRETE PILES, 
Section 1: Driven Cast In-situ Concrete Piles [CED 43: Soil 
and Foundation Engineering] 



Satyanarayan Gangaram Pitroda 
Invent a New India Using Knowledge 




Bhartrhari — Nitisatakam 
"Knowledge is such a treasure which cannot be stolen" 





BLANK PAGE 




^*-:gv 




^^35^* 



PROTECTED BY COPYRIGHT 



IS 2911 (Part 1 /Seel) : 2010 

Indian Standard 

DESIGN AND CONSTRUCTION OF PILE 
FOUNDATIONS — CODE OF PRACTICE 

PART 1 CONCRETE PILES 
Section 1 Driven Cast In-situ Concrete Piles 

( Second Revision ) 



ICS 91.100.30 : 93.020 



© BIS 2010 
BUREAU OF INDIAN STANDARDS 

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG 
NEW DELHI 110002 

May 2011 Price Group 8 



Soil and Foundation Engineering Sectional Committee, CED 43 



FOREWORD 

This Indian Standard (Part 1/Sec 1) (Second Revision) was adopted by the Bureau of Indian Standards, after 
the draft finalized by the Soil and Foundation Engineering Sectional Committee had been approved by the 
Civil Engineering Division Council. 

Piles find application in foundations to transfer loads from a structure to competent subsurface strata having 
adequate load-bearing capacity. The load transfer mechanism from a pile to the surrounding ground is 
complicated and is not yet fully understood, although application of piled foundations is in practice over 
many decades. Broadly, piles transfer axial loads either substantially by friction along its shaft and/or by 
the end-bearing. Piles are used where either of the above load transfer mechanism is possible depending 
upon the subsoil stratification at a particular site. Construction of pile foundations require a careful choice 
of piling system depending upon the subsoil conditions, the load characteristics of a structure and the 
limitations of total settlement, differential settlement and any other special requirement of a project. The 
installation of piles demands careful control on position, alignment and depth, and involve specialized skill 
and experience. 

This standard was originally published in 1964 and included provisions regarding driven cast in-situ piles, 
precast concrete piles, bored piles and under-reamed piles including load testing of piles. Subsequently the 
portion pertaining to under-reamed pile foundations was deleted and now covered in IS 2911 (Part 3) : 1980 
'Code of practice for design and construction of pile foundations: Part 3 Under-reamed piles (first revisiotiY . 
At that time it was also decided that the provisions regarding other types of piles should also be published 
separately for ease of reference and to take into account the recent developments in this field. Consequently 
this standard was revised in 1979 into three sections. Later, in 1984, a new section as (Part 1/Sec 4) was 
introduced in this part of the standard to cover the provisions of bored precast concrete piles. The portion 
relating to load test on piles has been covered in a separate part, namely, IS 2911 (Part 4) : 1984 'Code of 
practice for design and construction of pile foundations: Part 4 Load test on piles'. Accordingly IS 291 1 has 
been published in four parts. The other parts of the standard are: 

Part 2 Timber piles 

Part 3 Under-reamed piles 

Part 4 Load test on piles 

Other sections of Part 1 are: 

Section 2 Bored cast in-situ concrete piles 

Section 3 Driven precast concrete piles 

Section 4 Precast concrete piles in prebored holes 

It has been felt that the provisions regarding the different types of piles should be further revised to take 
into account the recent developments in this field. This revision has been brought out to incorporate these 
developments. 

In the present revision following major modifications have been made: 

a) Definitions of various terms have been modified as per the prevailing engineering practice. 

b) Procedures for calculation of bearing capacity, structural capacity, factor of safety, lateral load 
capacity, overloading, etc, have also been modified to bring them at par with the present practices. 

c) Design parameters with respect to adhesion factor, earth pressure coefficient, modulus of subgrade 
reaction, etc, have been revised to make them consistence with the outcome of modern research and 
construction practices. 

{Continued on third cover) 



{Continued from second cover) 

d) Provision has been made for use of any established dynamic pile driving formulae, instead of 
recommending any specific formula, to control the pile driving at site, giving due consideration to 
limitations of various formulae. 

e) Minimum grade of concrete to be used in pile foundations has been revised to M 25. 

Driven cast in-situ pile is formed in the ground by driving a casing, permanent or temporary, and subsequently 
filling in the hole with plain or reinforced concrete. For this type of pile the subsoil is displaced by the 
driving of the casing, which is installed with a plug or a shoe at the bottom. In case of the piles driven with 
temporary casings, known as uncased, the concrete poured in-situ comes in direct contact with the soil. The 
concrete may be rammed, vibrated or just poured, depending upon the particular system of piling adopted. 
This type of piles find wide application, where the pile is required to be taken to a greater depth to find 
adequate bearing strata or to develop adequate skin friction and also when the length of individual piles 
cannot be predetermined. 

The recommendations for detailing for earthquake-resistant construction given in IS 13920 : 1993 'Ductile 
detailing of reinforced concrete structures subjected to seismic forces — Code of practice' should be taken 
into consideration, where applicable (see also IS 4326 ; 1993 'Earthquake resistant design and construction 
of buildings — Code of practice'). 

The composition of the Committee responsible for the formulation of this standard is given in Annex E. 

For the purpose of deciding whether a particular requirement of this standard is complied with, the final 
value, observed or calculated, expressing the result of a test or analysis shall be rounded off in accordance 
with IS 2 ; 1960 'Rules for rounding off numerical values {revised)' . The number of significant places 
retained in the rounded off value should be the same as that of the specified value in this standard. 



IS 2911 (Part 1/Sec 1) : 2010 

Indian Standard 

DESIGN AND CONSTRUCTION OF PILE 
FOUNDATIONS — CODE OF PRACTICE 

PART 1 CONCRETE PILES 
Section 1 Driven Cast In-situ Concrete Piles 

( Second Revision ) 



1 SCOPE 

1.1 This standard (Part 1/Sec 1) covers the design 
and construction of driven cast in-situ concrete 
piles which transmit the load to the soil by 
resistance developed either at the pile tip by end- 
bearing or along the surface of the shaft by friction 
or by both. 

1.2 This standard is not applicable for use of driven 
cast in-situ concrete piles for any other purpose, for 
example, temporary or permanent retaining structure. 

2 REFERENCES 

The standards listed in Annex A contain provisions, 
which through reference in this text, constitute 
provisions of this standard. At the time of 
publication, the editions indicated were valid. All 
standards are subject to revision and parties to 
agreements based on this standard are encouraged to 
investigate the possibility of applying the most 
recent editions of the standards listed in Annex A. 

3 TERMINOLOGY 

For the purpose of this standard, the following 
definitions shall apply. 

3.1 Allowable Load — The load which may be 
applied to a pile after taking into account its 
ultimate load capacity, group effect, the allowable 
settlement, negative skin friction and other relevant 
loading conditions including reversal of loads, if 
any. 

3.2 Anchor Pile — An anchor pile means a pile 
meant for resisting pull or uplift forces. 

3.3 Batter Pile (Raker Pile) — The pile which is 
installed at an angle to the vertical using temporary 
casing or permanent liner 

3.4 Cut-off Level — It is the level where a pile is 
cut-off to support the pile caps or beams or any other 
structural components at that level. 

3.5 Driven Cast In-situ Pile — A pile formed 
within the ground by driving a casing of uniform 
diameter, or a device to provide enlarged base and 



subsequently filling the hole with reinforced 
concrete. For displacing the subsoil the casing is 
driven with a plug or a shoe at the bottom. When 
the casing is left permanently in the ground, it is 
termed as cased pile and when the casing is taken 
out, it is termed as uncased pile. The steel casing 
tube is tamped during its extraction to ensure proper 
compaction of concrete. 

3.6 Elastic Displacement — This is the magnitude 
of displacement of the pile head during rebound on 
removal of a given test load. This comprises two 
components: 

a) Elastic displacement of the soil participating 
in the load transfer, and 

b) Elastic displacement of the pile shaft. 

3.7 Factor of Safety — It is the ratio of the ultimate 
load capacity of a pile to the safe load on the pile. 

3.8 Follower Tube — A tube which is used 
following the main casing tube when adequate set is 
not obtained with the main casing tube and it 
requires to be extended further. The inner diameter 
of the follower tube should be the same as the inner 
diameter of the casing. The follower tube should be 
water-tight when driven in water-bearing strata. 

3.9 Gross Displacement — The total movement of 
the pile top under a given load. 

3.10 Initial Load Test — A test pile is tested to 
determine the load-carrying capacity of the pile by 
loading either to its ultimate load or to twice the 
estimated safe load. 

3.11 Initial Test Pile — One or more piles, which 
are not working piles, may be installed if required to 
assess the load-carrying capacity of a pile. These 
piles are tested either to their ultimate load capacity 
or to twice the estimated safe load. 

3.12 Load Bearing Pile — A pile formed in the 
ground for transmitting the load of a structure to the 
soil by the resistance developed at its tip and/or 
along its surface. It may be formed either vertically 
or at an inclination (batter pile) and may be required 
to resist uplift forces. 



1 



IS 2911 (Part 1/Sec 1) : 2010 



If the pile supports the load primarily by resistance 
developed at the pile tip or base it is called 'End- 
bearing pile' and, if primarily by friction along its 
surface, then 'Friction pile'. 

3.13 Net Displacement — The net vertical 
movement of the pile top after the pile has been 
subjected to a test load and subsequently released. 

3.14 Pile Spacing — The spacing of piles means the 
centre-to-centre distance between adjacent piles. 

3.15 Routine Test Pile — A pile which is selected 
for load testing may form a working pile itself, if 
subjected to routine load test up to not more than 
1.5 times the safe load. 

3.16 Safe Load — It is the load derived by applying 
a factor of safety on the ultimate load capacity of the 
pile or as determined from load test. 

3.17 Ultimate Load Capacity — The maximum 
load which a pile can carry before failure, that is, 
when the founding strata fails by shear as evidenced 
from the load settlement curve or the pile fails as a 
structural member. 

3.18 Working Load — The load assigned to a pile 
as per design. 

3.19 Working Pile — A pile forming part of the 
foundation system of a given structure. 

4 NECESSARY INFORMATION 

4.1 For the satisfactory design and construction of 
driven cast in-situ piles the following information 
would be necessary: 

a) Site investigation data as laid down under 
IS 1892. Sections of trial boring, 
supplemented, wherever appropriate, by 
penetration tests, should incorporate data/ 
information down to depth sufficiently 
below the anticipated level of founding of 
piles but this should generally be not less 
than 10 m beyond the pile founding level. 
Adequacy of the bearing strata should be 
ensured by supplementary tests, if required. 

b) The nature of the soil both around and 
beneath the proposed pile should be 
indicated on the basis of appropriate tests of 
strength, compressibility, etc. Ground water 
level and artesian conditions, if any, should 
also be recorded. Results of chemical tests 
to ascertain the sulphate, chloride and any 
other deleterious chemical content of soil 
and water should be indicated. 

c) For piling work in water, as in the case of 
bridge foundation, data on high flood levels, 
water level during the working season, 
maximum depth of scour, etc, and in the case 
of marine construction, data on high and low 



tide level, corrosive action of chemicals 
present and data regarding flow of water 
should be provided. 

d) The general layout of the structure showing 
estimated loads and moments at the top of 
pile caps but excluding the weight of the 
piles and caps should be provided. The top 
levels of finished pile caps shall also be 
indicated. 

e) All transient loads due to seismic, wind, 
water current, etc, indicated separately. 

f) In soils susceptible to liquefaction during 
earthquake, appropriate analysis may be 
done to determine the depth of liquefaction 
and consider the pile depth accordingly. 

4.2 As far as possible all informations given in 4.1 
shall be made available to the agency responsible 
for the design and/or construction of piles and/or 
foundation work. 

4.3 The design details of pile foundation shall give 
the information necessary for setting out and layout 
of piles, cut-off levels, finished cap level, layout and 
orientation of pile cap in the foundation plan and 
the safe capacity of each type of pile, etc. 

5 EQUIPMENTS AND ACCESSORIES 

5.1 The equipments and accessories would depend 
upon the type of driven cast in-situ piles chosen for 
a job after giving due considerations to the subsoil 
strata, ground-water conditions, types of founding 
material and the required penetration therein, 
wherever applicable. 

5.2 Among the commonly used plants, tools and 
accessories, there exists a large variety; suitability 
of which depends on the subsoil condition, manner 
of operation, etc. Brief definitions of some 
commonly used equipments are given below: 

5.2.1 Dolly — A cushion of hardwood or some 
suitable material placed on the top of the casing to 
receive the blows of the hammer. 

5.2.2 Drop Hammer (or Monkey) — Hammer, ram or 
monkey raised by a winch and allowed to fall under 
gravity. 

5.2.3 Single or Double Acting Hajnmer — A hammer 
operated by steam compressed air or internal 
combustion, the energy of its blows being derived 
mainly from the source of motive power and not from 
gravity alone. 

5.2.4 Hydraulic Hammer — A hammer operated by 
a hydraulic fluid can be used with advantage for 
increasing the energy of blow. 

5.2.5 Kentledge — Dead weight used for applying 
a test load on a pile. 



IS 2911 (Part 1/Sec 1) : 2010 



5.2.6 Pile Rig — A movable steel structure for driving 
piles in the correct position and alignment by means 
of a hammer operating in the guides of the frame. 

6 DESIGN CONSIDERATIONS 

6.1 General 

Pile foundations shall be designed in such a way that 
the load from the structure can be transmitted to the 
sub-surface with adequate factor of safety against 
shear failure of sub-surface and without causing such 
settlement (differential or total), which may result in 
structural damage and/or functional distress under 
permanent/transient loading. The pile shaft should 
have adequate structural capacity to withstand all 
loads (vertical, axial or otherwise) and moments 
which are to be transmitted to the subsoil and shall 
be designed according to IS 456. 

6.2 Adjacent Structures 

6.2.1 When working near existing structures, care 
shall be taken to avoid damage to such structures. 
IS 2974 (Part 1) may be used as a guide for studying 
qualitatively the effect of vibration on persons and 
structures. 

6.2.2 In case of deep excavations adjacent to piles, 
proper shoring or other suitable arrangement shall be 
made to guard against undesired lateral movement 
of soil. 

6.3 Pile Capacity 

The load-carrying capacity of a pile depends on the 
properties of the soil in which it is embedded. Axial 
load from a pile is normally transmitted to the soil 
through skin friction along the shaft and end-bearing 
at its tip. A horizontal load on a vertical pile is 
transmitted to the subsoil primarily by horizontal 
subgrade reaction generated in the upper part of the 
shaft. Lateral load capacity of a single pile depends 
on the soil reaction developed and the structural 
capacity of the shaft under bending. It would be 
essential to investigate the lateral load capacity of 
the pile using appropriate values of horizontal 
subgrade modulus of the soil. Alternatively, piles 
may be installed in rake. 

6.3.1 The ultimate load capacity of a pile may be 
estimated by means of static formula on the basis of 
soil test results, or by using a dynamic pile formula 
using data obtained during driving the pile. 
However, dynamic pile driving formula should be 
generally used as a measure to control the pile 
driving at site. Pile capacity should preferably be 
confirmed by initial load tests [see IS 2911 (Part 4)]. 

The settlement of pile obtained at safe load/working 
load from load-test results on a single pile shall not 



be directly used for estimating the settlement of a 
structure. The settlement may be determined on the 
basis of subsoil data and loading details of the 
structure as a whole using the principles of soil 
mechanics. 

6.3.1.1 Static formula 

The ultimate load capacity of a single pile may be 
obtained by using static analysis, the accuracy being 
dependent on the reliability of the soil properties for 
various strata. When computing capacity by static 
formula, the shear strength parameters obtained from 
a limited number of borehole data and laboratory 
tests should be supplemented, wherever possible by 
in-situ shear strength obtained from field tests. The 
two separate static formulae, commonly applicable 
for cohesive and non-cohesive soil respectively, are 
indicated in Annex B. Other formula based on static 
cone penetration test {see IS 4968 (Parts 1, 2 and 3)] 
and standard penetration test {see IS 2131) are given 
in B-3 and B-4. 

6.3.1.2 Dynamic formula 

Any established dynamic formula may be used to 
control the pile driving at site giving due 
consideration to limitations of various formulae. 

Whenever double acting diesel hammers or hydraulic 
hammers are used for driving of piles, manufacturer's 
guidelines about energy and set criteria may be 
referred to. Dynamic formulae are not directly 
applicable to cohesive soil deposits, such as, 
saturated silts and clays as the resistance to impact 
of the tip of the casing will be exaggerated by their 
low permeability while the frictional resistance on 
the sides is reduced by lubrication. 

6.3.2 Uplift Capacity 

The uplift capacity of a pile is given by sum of the 
frictional resistance and the weight of the pile 
(buoyant or total as relevant). The recommended 
factor of safety is 3.0 in the absence of any pullout 
test results and 2.0 with pullout test results. Uplift 
capacity can be obtained from static formula {see 
Annex B) by ignoring end-bearing but adding 
weight of the pile (buoyant or total as relevant). 

6.4 Negative Skin Friction or Dragdown Force 

When a soil stratum, through which a pile shaft has 
penetrated into an underlying hard stratum, 
compresses as a result of either it being 
unconsolidated or it being under a newly placed fill 
or as a result of remoulding during driving of the 
pile, a dragdown force is generated along the pile 
shaft up to a point in depth where the surrounding 
soil does not move downward relative to the pile 



IS 2911 (Part 1/Sec 1) : 2010 



shaft. Existence of such a phenomenon shall be 
assessed and suitable correction shall be made to the 
allowable load where appropriate. 

6.5 Structural Capacity 

The piles shall have necessary structural strength to 
transmit the loads imposed on it, ultimately to the 
soil. In case of uplift, the structural capacity of the 
pile, that is, under tension should also be considered. 

6.5.1 Axial Capacity 

Where a pile is wholely embedded in the soil 
(having an undrained shear strength not less than 
0.01 N/mm-), its axial load-carrying capacity is not 
necessarily limited by its strength as a long column. 
Where piles are installed through very weak soils 
(having an undrained shear strength less than 
0.01 N/mm-), special considerations shall be made 
to determine whether the shaft would behave as a 
long column or not. If necessary, suitable reductions 
shall be made for its structural strength following the 
normal structural principles covering the buckling 
phenomenon. 

When the finished pile projects above ground level 
and is not secured against buckling by adequate 
bracing, the effective length will be governed by the 
fixity imposed on it by the structure it supports and 
by the nature of the soil into which it is installed. 
The depth below the ground surface to the lower 
point of contraflexure varies with the type of the 
soil. In good soil the lower point of contraflexure 
may be taken at a depth of 1 m below ground surface 
subject to a minimum of 3 times the diameter of the 
shaft. In weak soil (undrained shear strength less 
than 0.01 N/mm-) such as, soft clay or soft silt, this 
point may be taken at about half the depth of 
penetration into such stratum but not more than 3 m 
or 10 times the diameter of the shaft whichever is 
more. The degree of fixity of the position and 
inclination of the pile top and the restraint provided 
by any bracing shall be estimated following accepted 
structural principles. 

The permissible stress shall be reduced in accordance 
with similar provision for reinforced concrete 
columns as laid down in IS 456. 

6.5.2 Lateral Load Capacity 

A pile may be subjected to lateral force for a number 
of causes, such as, wind, earthquake, water current, 
earth pressure, effect of moving vehicles or ships, 
plant and equipment, etc. The lateral load capacity 
of a single pile depends not only on the horizontal 
subgrade modulus of the surrounding soil but also 
on the structural strength of the pile shaft against 
bending, consequent upon application of a lateral 



load. While considering lateral load on piles, effect 
of other co-existent loads, including the axial load 
on the pile, should be taken into consideration for 
checking the structural capacity of the shaft. A 
recommended method for the pile analysis under 
lateral load is given in Annex C. 

Because of limited information on horizontal 
subgrade modulus of soil and pending refinements 
in the theoretical analysis, it is suggested that the 
adequacy of a design should be checked by an 
actual field load test. In the zone of soil susceptible 
to liquefaction the lateral resistance of the soil shall 
not be considered. 

6.5.2.1 Fixed and free head conditions 

A group of three or more pile connected by a rigid 
pile cap shall be considered to have fixed head 
condition. Caps for single piles must be 
interconnected by grade beams in two directions and 
for twin piles by grade beams in a line transverse to 
the common axis of the pair so that the pile head is 
fixed. In all other conditions the pile shall be taken 
as free headed. 

6.5.3 Raker Piles 

Raker piles are normally provided where vertical piles 
cannot resist the applied horizontal forces. Generally 
the rake will be limited to 1 horizontal to 6 vertical. 
In the preliminary design, the load on a raker pile is 
generally considered to be axial. The distribution of 
load between raker and vertical piles in a group may 
be determined by graphical or analytical methods. 
Where necessary, due consideration should be made 
for secondary bending induced as a result of the pile 
cap movement, particularly when the cap is rigid. 
Free-standing raker piles are subjected to bending 
moments due to their own weight or external forces 
from other causes. Raker piles, embedded in fill or 
consolidating deposits, may become laterally loaded 
owing to the settlement of the surrounding soil. In 
consolidating clay, special precautions, like provision 
of permanent casing should be taken for raker piles. 

6.6 Spacing of Piles 

The minimum centre-to-centre spacing of pile is 
considered from three aspects, namely, 

a) practical aspects of installing the piles, 

b) diameter of the pile, and 

c) nature of the load transfer to the soil and 
possible reduction in the load capacity of 
piles group. 

NOTE — In the case of piles of non-circular cross- 
section, diameter of the circumscribing circle shall 
be adopted. 



IS 2911 (Part 1/Sec 1) : 2010 



6.6.1 In case of piles founded on hard stratum and 
deriving their capacity mainly from end-bearing the 
minimum spacing shall be 2.5 times the diameter of 
the circumscribing circle corresponding to the cross- 
section of the pile shaft. In case of piles resting on 
rock, the spacing of two times the said diameter may 
be adopted. 

6.6.2 Piles deriving their load-carrying capacity 
mainly from friction shall be spaced sufficiently 
apart to ensure that the zones of soils from which the 
piles derive their support do not overlap to such an 
extent that their bearing values are reduced. 
Generally the spacing in such cases shall not be less 
than 3 times the diameter of the pile shaft. 

6.7 Pile Groups 

6.7.1 In order to determine the load-carrying 
capacity of a group of piles a number of efficiency 
equations are in use. However, it is difficult to 
establish the accuracy of these efficiency equations 
as the behaviour of pile group is dependent on many 
complex factors. It is desirable to consider each case 
separately on its own merits. 

6.7.2 The load-carrying capacity of a pile group 
may be equal to or less than the load-carrying 
capacity of individual piles multiplied by the number 
of piles in the group. The former holds true in case 
of friction piles, driven into progressively stiffer 
materials or in end-bearing piles. For driven piles in 
loose sandy soils, the group capacity may even be 
higher due to the effect of compaction. In such cases 
a load test may be carried out on a pile in the group 
after all the piles in the group have been installed. 

6.7.3 In case of piles deriving their support mainly 
from friction and connected by a rigid pile cap, the 
group may be visualized as a block with the piles 
embedded within the soil. The ultimate load 
capacity of the group may then be obtained by 
taking into account the frictional capacity along the 
perimeter of the block and end-bearing at the bottom 
of the block using the accepted principles of soil 
mechanics. 

6.7.3.1 When the cap of the pile group is cast 
directly on reasonably firm stratum which supports 
the piles, it may contribute to the load-carrying 
capacity of the group. This additional capacity 
along with the individual capacity of the piles 
multiplied by the number of piles in the group shall 
not be more than the capacity worked out according 
to 6.7.3. 

6.7.4 When a pile group is subjected to moment 
either from superstructure or as a consequence of 
inaccuracies of installation, the adequacy of the pile 
group in resisting the applied moment should be 
checked. In case of a single pile subjected to 



moment due to lateral loads or eccentric loading, 
beams may be provided to restrain the pile cap 
effectively from lateral or rotational movement. 

6.7.5 In case of a structure supported on single piles/ 
group of piles resulting in large variation in the 
number of piles from column-to-column it may result 
in excessive differential settlement. Such differential 
settlement should be either catered for in the 
structural design or it may be suitably reduced by 
judicious choice of variations in the actual pile 
loading. For example, a single pile cap may be 
loaded to a level higher than that of the pile in a 
group in order to achieve reduced differential 
settlement between two adjacent pile caps supported 
on different number of piles. 

6.8 Factor of Safety 

6.8.1 Factor of safety should be chosen after 
considering, 

a) the reliability of the calculated value of 
ultimate load capacity of a pile, 

b) the types of superstructure and the type of 
loading, and 

c) allowable total/differential settlement of the 
structure. 

6.8.2 When the ultimate load capacity is determined 
from either static formula or dynamic formula, the 
factor of safety would depend on the reliability of 
the formula and the reliability of the subsoil 
parameters used in the computation. The minimum 
factor of safety on static formula shall be 2.5. The 
final selection of a factor of safety shall take into 
consideration the load settlement characteristics of 
the structure as a whole at a given site. 

6.8.3 Higher value of factor of safety for 
determining the safe load on piles may be adopted, 
where, 

a) settlement is to be limited or unequal 
settlement avoided, 

b) large impact or vibrating loads are expected, 
and 

c) the properties of the soil may deteriorate with 
time. 

6.9 Transient Loading 

The maximum permissible increase over the safe load 
of a pile, as arising out of wind loading, is 
25 percent. In case of loads and moments arising out 
of earthquake effects, the increase of safe load on a 
single pile may be limited to the provisions 
contained in IS 1893 (Part 1). For transient loading 
arising out of superimposed loads, no increase is 
allowed. 



IS 2911 (Part 1/Sec 1) : 2010 



6.10 Overloading 

When a pile in a group, designed for a certain safe 
load is found, during or after execution, to fall just 
short of the load required to be carried by it, an 
overload up to 10 percent of the pile capacity may 
be allowed on each pile. The total overloading on 
the group should not, however, be more than 
10 percent of the capacity of the group subject to the 
increase of the load on any pile being not more than 
25 percent of the allowable load on a single pile. 

6.11 Reinforcement 

6.11.1 The design of the reinforcing cage varies 
depending upon the driving and installation 
conditions, the nature of the subsoil and the nature 
of load to be transmitted by the shaft-axial, or 
otherwise. The minimum area of longitudinal 
reinforcement of any type or grade within the pile 
shaft shall be 0.4 percent of the cross-sectional area 
of the pile shaft. The minimum reinforcement shall 
be provided throughout the length of the shaft. 

6.11.2 The curtailment of reinforcement along the 
depth of the pile, in general, depends on the type of 
loading and subsoil strata. In case of piles subjected 
to compressive load only, the designed quantity of 
reinforcement may be curtailed at appropriate level 
according to the design requirements. For piles 
subjected to uplift load, lateral load and moments, 
separately or with compressive loads, it would be 
necessary to provide reinforcement for the full depth 
of pile. In soft clays or loose sands, or where there 
may be danger to green concrete due to driving of 
adjacent piles, the reinforcement should be provided 
to the full pile depth, regardless of whether or not it 
is required from uplift and lateral load 
considerations. However, in all cases, the minimum 
reinforcement specified in 6.11.1 shall be provided 
throughout the length of the shaft. 

6.11.3 Piles shall always be reinforced with a 
minimum amount of reinforcement as dowels 
keeping the minimum bond length into the pile shaft 
below its cut-off level and with adequate projection 
into the pile cap, irrespective of design requirements. 

6.11.4 Clear cover to all main reinforcement in pile 
shaft shall be not less than 50 mm. The laterals of a 
reinforcing cage may be in the form of links or 
spirals. The diameter and spacing of the same is 
chosen to impart adequate rigidity of the reinforcing 
cage during its handling and installations. The 
minimum diameter of the links or spirals shall be 
8 mm and the spacing of the links or spirals shall be 
not less than 150 mm. Stiffner rings preferably of 
16 mm diameter at every 1.5 m centre-to-centre 
should be provided along the length of the cage for 
providing rigidity to reinforcement cage. Minimum 



6 numbers of vertical bars shall be used for a circular 
pile and minimum diameter of vertical bar shall be 
12 mm. The clear horizontal spacing between the 
adjacent vertical bars shall be four times the 
maximum aggregate size in concrete. If required, the 
bars can be bundled to maintain such spacing. 

6.12 Design of Pile Cap 

6.12.1 The pile caps may be designed by assuming 
that the load from column is dispersed at 45° from 
the top of the cap to the mid-depth of the pile cap 
from the base of the column or pedestal. The 
reaction from piles may also be taken to be 
distributed at 45° from the edge of the pile, up to 
the mid-depth of the pile cap. On this basis the 
maximum bending moment and shear forces should 
be worked out at critical sections. The method of 
analysis and allowable stresses should be in 
accordance with IS 456. 

6.12.2 Pile cap shall be deep enough to allow for 
necessary anchorage of the column and pile 
reinforcement. 

6.12.3 The pile cap should be rigid enough so that 
the imposed load could be distributed on the piles 
in a group equitably. 

6.12.4 In case of a large cap, where differential 
settlement may occur between piles under the same 
cap, due consideration for the consequential moment 
should be given. 

6.12.5 The clear overhang of the pile cap beyond 
the outermost pile in the group shall be a minimum 
of 150 mm. 

6.12.6 The cap is generally cast over a 75 mm thick 
levelling course of concrete. The clear cover for 
main reinforcement in the cap slab shall not be less 
than 60 mm. 

6.12.7 The embedment of pile into cap should be 

75 mm. 

6.13 The design of grade beam if used shall be as 
given in IS 2911 (Part 3). 

7 MATERIALS AND STRESSES 
7.1 Cement 

The cement used shall be any of the following: 

a) 33 Grade ordinary Portland cement 
conforming to IS 269, 

b) 43 Grade ordinary Portland cement 
conforming to IS 8112, 

c) 53 Grade ordinary Portland cement 
conforming to IS 12269, 

d) Rapid hardening Portland cement 
conforming to IS 8041, 



IS 2911 (Part 1/Sec 1) : 2010 



e) Portland slag cement conforming to IS 455, 

f) Portland pozzolana cement (fly ash based) 
conforming to IS 1489 (Part 1), 

g) Portland pozzolana cement (calcined clay 
based) conforming to IS 1489 (Part 2), 

h) Hydrophobic cement conforming to IS 8043, 

j) Low beat Portland cement conforming to 
IS 12600, and 

k) Sulphate resisting Portland cement 
conforming to IS 12330. 

7.2 Steel 

Reinforcement steel shall be any of the following: 

a) Mild steel and medium tensile steel bars 
conforming to IS 432 (Part 1), 

b) High strength deformed steel bars 
conforming to IS 1786, and 

c) Structural steel conforming to IS 2062. 

7.3 Concrete 

7.3.1 Consistency of concrete to be used for driven 
cast in-situ piles shall be consistent with the method 
of installation of piles. Concrete shall be so designed 
or chosen as to have a homogeneous mix having a 
slump/workability consistent with the method of 
concreting under the given conditions of pile 
installation. 

7.3.2 The slump should be 150 to 180 mm at the 
time of pouring. 

7.3.3 The minimum grade of concrete to be used for 
piling shall be M 25. For sub aqueous concrete, the 
requirements specified in IS 456 shall be followed. The 
minimum cement content shall be 400 kg/m^. However, 
with proper mix design and use of proper admixtures 
the cement content may be reduced but in no case the 
cement content shall be less than 350 kg/m^. 

7.3.4 For the concrete, water and aggregates 
specifications laid down in IS 456 shall be followed 
in general. 

7.3.5 The average compressive stress under working 
load should not exceed 25 percent of the specified 
works cube strength at 28 days calculated on the 
total cross-sectional area of the pile. Where the 
casing of the pile is permanent, of adequate thickness 
and of suitable shape, the allowable compressive 
stress may be increased. 

8 WORKMANSHIP 

8.1 Control of Alignment 

Piles shall be installed as accurately as possible 
according to the design and drawings either 



vertically or to the specified batter. Greater care 
should be exercised in respect of installation of 
single piles or piles in two pile groups. As a guide, 
for vertical piles, an angular deviation of 1.5 percent 
and for raker piles, a deviation of 4 percent should 
not be exceeded. Piles should not deviate more than 
75 mm or DI6 whichever is less (75 mm or D/10 
whichever is more in case of piles having diameter 
more than 600 mm) from their designed positions at 
the working level. In the case of single pile under a 
column the positional deviation should not be more 
than 50 mm or DI6 whichever is less (100 mm in case 
of piles having diameter more than 600 mm). Greater 
tolerance may be prescribed for piles cast over water 
and for raking piles. For piles to be cut-off at a 
substantial depth below the working level, the 
design shall provide for the worst combination of the 
above tolerances in position and inclination. In case 
of piles deviating beyond these limits and to such 
an extent that the resulting eccentricity can not be 
taken care of by redesign of the pile cap or pile ties, 
the piles shall be replaced or supplemented by 
additional piles. 

8.2 Sequence of Piling 

8.2.1 In a pile group the sequence of installation of 
piles shall normally be from the center to the 
periphery of the group or from one side to the other. 

8.2.2 Driving a Group of Friction Piles 

Driving piles in loose sand tends to compact the 
sand, which in turn, increases the skin friction. In 
case where stiff clay or dense sand layers have to be 
penetrated, similar precautions described in 8.2.1 
needs to be taken. However, in the case of very soft 
soils, the driving may have to proceed from outside 
to inside so that the soil is restricted from flowing 
out during operations. 

8.3 Concreting and Withdrawal of Casing Tube 

8.3.1 Whenever condition indicates ingress of water, 
casing tube shall be examined for any water 
accumulation and care shall be taken to place 
concrete in a reasonably dry condition. 

8.3.2 The top of concrete in a pile shall be brought 
above the cut-off level to permit removal of all 
laitance and weak concrete before capping and to 
ensure good concrete at cut-off level. The 
reinforcing cages shall be left with adequate 
protruding length above cut-off level for proper 
embedment into the pile cap. 

8.3.3 Where cut-off level is less than 1.50 m below 
working level, the concrete shall be cast to a 
minimum of 600 mm above the cut-off level. In case 
the cut-off is at deeper level, the empty bore shall be 



IS 2911 (Part 1/Sec 1) : 2010 



filled with lean concrete or suitable material, 
wherever the weight of fresh concrete in the casing 
pipe is found inadequate to counteract upward 
hydrostatic pressure at any level below the cut-off 
level. 

Also before initial withdrawal of the casing tube, 
adequate quantity of concrete shall be placed into 
the casing to counter the hydrostatic pressure at pile 
tip. 

8.4 Defective Piles 

8.4.1 In case defective piles are formed, they shall 
be left in place and additional piles as necessary 
shall be provided. 

8.4.2 If there is a major variation in the depths at 
which adjacent piles in a group meet refusal, a 
boring may be made nearby to ascertain the cause of 
such difference. If the boring shows that the strata 
contain pockets of highly compressive material 
below the level of shorter pile, it may be necessary 
to take such piles to a level below the bottom of the 
zone, which shows such pockets. 

8.5 Deviations 

Any deviation from the designed location, alignment 
or load-carrying capacity of any pile shall be noted 
and adequate measures taken to check the design 
well before the concreting of the pile cap and grade 
beams are done. 



8.6 While removing excess concrete or laitance 
above cut-off level, manual chipping shall be 
permitted after three days of pile concreting. 
Pneumatic tools shall be permitted only after seven 
days after casting. Before chipping/breaking the 
pile top, a groove shall be formed all around the pile 
diameter at the required cut-off level. 

8.7 Recording of Data 

8.7.1 A competent inspector shall be maintained at 
site to record necessary information during 
installation of piles and the data to be recorded shall 
essentially contain the following: 

a) Sequence of installation of piles in a group. 



b) 
c) 



Type and size of driving hammer and its 
stroke. 



Dimensions of the pile including the 
reinforcement details and mark of the pile, 

d) Cut-off level and working level, 

e) Depth driven, 

f) Time taken for driving and for concreting 
recorded separately, and 

g) Any other important observations, during 
driving, concreting and after withdrawal 
of casing tube. 

8.7.2 Typical data sheet for recording piling data are 
shown in Annex D. 



ANNEX A 

(Clause 2) 

LIST OF REFERRED INDIAN STANDARDS 



IS No. 
269 ; 1989 



432 (Part 1) 
1982 



455 : 1989 

456 : 2000 

1489 

(Part 1) ; 1991 
(Part 2) : 1991 



Title 

Ordinary Portland cement, 33 

grade — Specification (fourth 

revision) 

Specification for mild steel and 

medium tensile steel bars and 

hard-drawn steel wire for concrete 

reinforcement: Part 1 Mild steel 

and medium tensile steel bars 

(third revision) 

Portland slag cement — 

Specification (fourth revision) 

Plain and reinforced concrete — 

Code of practice (fourth revision) 

Portland-pozzolana cement — 

Specification; 

Fly ash based (third revision) 

Calcined clay based (third 

revision) 



IS No. Title 

1786 ; 1985 Specification for high strength 

deformed steel bars and wires for 
concrete reinforcement (third 
revision) 

1892 ; 1979 Code of practice for sub-surface 

investigations for foundations 
(first revision) 

1893 (Part 1) : Criteria for earthquake resistant 
2002 design of structures : Part 1 

General provision and buildings 

(fifth revision) 
2062 : 2006 Hot rolled low, medium and high 

tensile structural steel (sixth 

revision) 
2131 : 1981 Method for standard penetration 

test for soils (first revision) 
2911 Code of practice for design and 

construction of pile foundations : 
(Part 3) : 1980 Under-reamed piles (first 

revision) 



IS 2911 (Part 1/Sec 1) : 2010 



IS No. Title 

(Part 4) : 1984 Load test on piles (first revision) 

291 A (Part 1) : Code of practice for design and 

1982 construction of machine 

foundations: Part 1 Foundation 

for reciprocating type machines 

{second revision) 

4968 Method for sub-surface sounding 

for soils; 

(Part 1) : 1976 Dynamic method using 50 mm 
cone without bentonite slurry 
{first revision) 

(Part 2) : 1976 Dynamic method using cone and 
bentonite slurry {first revision) 

(Part 3) : 1976 Static cone penetration test {first 
revision) 



IS No. Title 

6403 : 1981 Code of practice for determination 

of bearing capacity of shallow 
foundations {first revision) 

8041 : 1990 Rapid hardening Portland cement 

— Specification {second revision) 

8043 : 1991 Hydrophobic Portland cement — 

Specification {second revision) 

8112 : 1989 43 grade ordinary Portland cement 

— Specification {first revision) 

12269 : 1987 Specification for 53 grade 
ordinary Portland cement 

12330 : 1988 Specification for sulphate 
resisting Portland cement 

12600: 1989 Portland cement, low heat — 
Specification 



ANNEX B 

(Clauses 6.3.1.1 and 6.3.2) 

LOAD-CARRYING CAPACITY OF PILES — STATIC ANALYSIS 



B-1 PILES IN GRANULAR SOILS 

The ultimate load capacity {Q ) of piles, in kN, in 
granular soils is given by the following formula: 

Q^=A^{V2DyNy +P^N^ )+i:L,^A.tan5A, ...(1) 

The first term gives end bearing resistance and the 
second term gives skin friction resistance. 

where 

A = cross-sectional area of pile tip, in m-; 

D = diameter of pile shaft, in m; 

Y = effective unit weight of the soil at pile 
tip, in kN/m^; 

A^^ = bearing capacity factors depending upon 
and N^^ the angle of internal friction, (|) at pile tip; 

P^ = effective overburden pressure at pile tip, 
in kN/m^ {see Note 5); 



8 

I 

A 



summation for layers 1 to n in which pile 
is installed and which contribute to 
positive skin friction; 

coefficient of earth pressure applicable 
for the ith layer {see Note 3); 

effective overburden pressure for the ;th 
layer, in kN/m-; 

angle of wall friction between pile and 
soil for the ith layer; and 

surface area of pile shaft in the /th layer, 
in m-. 



NOTES 

1 Ny factor can be taken for general shear failure 
according to IS 6403. 

2 N factor will depend on the nature of soil, type of 
pile, the L/D ratio and its method of construction. The 
values applicable for driven piles are given in Fig. 1. 

3 K, the earth pressure coefficient depends on the 
nature of soil strata, type of pile, spacing of pile and 
its method of construction. For driven piles in loose 
to dense sand with if varying between 30° and 40°, 
K values in the range of 1 to 2 may be used. 

4 5, the angle of wall friction may be taken equal to 
the friction angle of the soil around the pile stem. 

5 In working out pile capacity by static formula, the 
maximum effective overburden at the pile tip should 
correspond to the critical depth, which may be taken 
as 15 times the diameter of the pile shaft for c^ < 30° 
and increasing to 20 times for if > 40°. 

6 For piles passing through cohesive strata and 
terminating in a granular stratum, a penetration of at 
least twice the diameter of the pile shaft should be 
given into the granular stratum. 

B-2 PILES IN COHESIVE SOILS 

The ultimate load capacity {QJ of piles, in kN, in 
cohesive soils is given by the following formula: 



a=Ap^cCp+iL,«,cA, 



(2) 



p -c p 

The first term gives the end-bearing resistance and 
the second term gives the skin friction resistance. 

where 

A = cross-sectional area of pile tip, in m^; 

N, = bearing capacity factor, may be taken 
as 9; 



IS 2911 (Part 1/Sec 1) : 2010 



500 



5 iCO 



CL 

< 
(J 

o 



50 



10 

















y 



















J 


/ 








^ 








/ 










/ 








/ 








/ 








/ 


/ 









20 



2S 



3(> 



35 



4a 



4€ 



AfiHSLE OF IfrJTiFWAL FRICTION. % 



Fig. 1 Bearing Capacity Factor, A^ for Driven Piles 



c = average cohesion at pile tip, in kN/m-; 

/ ,. = summation for layers 1 to n in which the 
pile is installed and which contribute to 
positive skin friction; 

ttj = adhesion factor for the /th layer 
depending on the consistency of soil, 
{see Note); 

c. = average cohesion for the /th layer, in 
kN/m-; and 

A . = surface area of pile shaft in the /th layer. 



z. 
w 

X 

a. 
■c 



Id 



HA 



f\.& 



04 



Q2 







\ 




















\ 


\ 




















\ 


\ 


^^ 




















V 


^ 





























20 ^0 60 90 10Q 12{] I'O 1W 100 203 



NOTE — The value of adhesion factor, a depends 
on the undrained shear strength of the clay and may 
be obtained from Fig. 2. 



B-3 USE OF STATIC CONE PENETRATION 
DATA 



UNDRMfED SHEAR STnEUGTH. C u |kH,yn^| 
(FOR C u ■: 4(5 fcl*m=. 1 AKt e( - 1 ) 

Fig. 2 Variation of a with C 

u 

B-3. 2 Ultimate end bearing resistance (q ), in 
B-3.1 When full static cone penetration data are kN/m-, may be obtained as: 
available for the entire depth, the following , 

correlation may be used as a guide for the z ^Ici 

determination of ultimate load capacity of a pile. 1u — ^ 



10 



IS 2911 (Part 1/Sec 1) : 2010 



where 
q^g = average static cone resistance over a depth 

of 2D below the pile tip, in kN/m-; 
q^^ = minimum static cone resistance over the 

same 2D below the pile tip, in kN/m-; 
q^^ = average of the envelope of minimum static 

cone resistance values over the length of 

pile of 8Z) above the pile tip, in kN/m^; and 
D = diameter of pile shaft. 

B-3.3 Ultimate skin friction resistance can be 
approximated to local side friction (/), in kN/m^, 
obtained from static cone resistance as given in 
Table 1. 

Table 1 Side Friction for Different Types of Soil 



SI 


Type of Soil 


Local Side Friction, /^ 


No. 




kN/m^ 


(1) 


(2) 


(3) 


i) 


g^ less than 1 000 kN/m- 


qJ30 <f^< ql\0 


ii) 


Clay 


qJ25 <f^< 2qJ25 


iii) 


Silty clay and silty sand 


qjl00<f\< qJ25 


iv) 


Sand 


qJWO <f^< qJ50 


V) 


Coarse sand and gravel 
q^ = cone resistance, in kN/m- 


qJlOQ < f^< qjl50 



B-3.4 The correlation between standard penetration 
resistance, N (blows/30 cm) and static cone 
resistance, q , in kN/m- as given in Table 2 may be 
used for working out the end-bearing resistance and 
skin friction resistance of piles. This correlation 
should only be taken as a guide and should 
preferably be established for a given site as they can 
substantially vary with the grain size, Atterberg 
limits, water table, etc. 

Table 2 Co-relation Between A' and q^ for 
Different Types of Soil 



SI 




Type of Soil 


qJN 


No. 








(1) 




(2) 


(3) 


i) 


Clay 




150-200 


ii) 


Silts, 


sandy silts and slightly 


200-250 




cohesive silt-sand mixtures 




iii) 


Clean 


fine to medium sand 


300-400 




and slightly silty sand 




iv) 


Coarse sand and sands with 


500-600 




little : 


gravel 




V) 


Sandy 


gravel and gravel 


800-1 000 



B-4 USE OF STANDARD PENETRATION 
TEST DATA FOR COHESIONLESS SOIL 

B-4.1 The correlation suggested by Meyerhof using 
standard penetration resistance. A' in saturated 
cohesionless soil to estimate the ultimate load 
capacity of driven pile is given below. The ultimate 
load capacity of pile {Q ), in kN, is given as: 



U 



a=4oyv-^A^+ 



050 



.(3) 



The first term gives the end-bearing resistance and 
the second term gives the frictional resistance. 

where 

N = average N value at pile tip; 

L^ = length of penetration of pile in the bearing 
strata, in m; 

D = diameter or minimum width of pile shaft, 
in m; 

A = cross-sectional area of pile tip, in m^; 
j\f = average N along the pile shaft; and 
A = surface area of pile shaft, in m^. 

NOTE — The end-bearing resistance should not 

exceed 400 NA . 

p 

B-4. 2 For non-plastic silt or very fine sand the 
equation has been modified as; 



a=30^-^A +- 



NA 



(4) 



D " 0.60 
The meaning of all terms is same as for equation 3. 

B-5 FACTOR OF SAFETY 

The minimum factor of safety for arriving at the safe 
pile capacity from the ultimate load capacity 
obtained by using static formulae shall be 2.5. 

B-6 PILES IN STRATIFIED SOIL 

In stratified soil/C-(|) soil, the ultimate load capacity 
of piles should be determined by calculating the end- 
bearing and skin friction in different strata by using 
appropriate expressions given in B-1 and B-2. 



11 



IS 2911 (Part 1/Sec 1) : 2010 



ANNEX C 
(Clause 6.5.2) 

ANALYSIS OF LATERALLY LOADED PILES 



C-1 GENERAL 

C-1.1 The ultimate resistance of a vertical pile to a 
lateral load and the deflection of the pile as the load 
builds up to its ultimate value are complex matters 
involving the interaction between a semi-rigid 
structural element and soil which deforms partly 
elastically and partly plastically. The failure 
mechanisms of an infinitely long pile and that of a 
short rigid pile are different. The failure mechanisms 
also differ for a restrained and unrestrained pile head 
conditions. 

Because of the complexity of the problem only a 
procedure for an approximate solution, that is, 
adequate in most of the cases is presented here. 
Situations that need a rigorous analysis shall be 
dealt with accordingly. 

C-1.2 The first step is to determine, if the pile will 
behave as a short rigid unit or as an infinitely long 
flexible member. This is done by calculating the 
stiffness factor R or Tfor the particular combination 
of pile and soil. 

Having calculated the stiffness factor, the criteria for 
behaviour as a short rigid pile or as a long elastic 
pile are related to the embedded length L of the pile. 
The depth from the ground surface to the point of 
virtual fixity is then calculated and used in the 
conventional elastic analysis for estimating the 
lateral deflection and bending moment. 

C-2 STIFFNESS FACTORS 

C-2.1 The lateral soil resistance for granular soils 
and normally consolidated clays which have varying 
soil modulus is modelled according to the equation; 



P_ 

y 



■■\^ 



where 
P 



= lateral soil reaction per unit length of pile 
at depth z below ground level; 
y = lateral pile deflection; and 
Tji^ = modulus of subgrade reaction for which 
the recommended values are given in 
Table 3. 



Table 3 Modulus of Subgrade Reaction for 
Granular Soils, T]^, in kN/m' 



SI Soil Type 
No. (Bl 


N 
ows/30 

(3) 


cm) 


Range of T||^ 
kN/m' X 10' 


(1) (2) 


Dry Submerged 
(4) (5) 


i) Very loose sand 


0-4 




< 0.4 < 0.2 


ii) Loose sand 


4-10 




0.4-2.5 0.2-1.4 


ill) Medium sand 


10-35 




2.5-7.5 1.4-5.0 


iv) Dense sand 


> 35 




7.5-20.0 5.0-12.0 


NOTE— The Tl^ 
intermediate standard 


values may 
penetration 


be interpolated for 
values, N. 



C-2.2 The lateral soil resistance for preloaded clays 
with constant soil modulus is modelled according to 
the equation: 



= K 



where 



K 



k 
L5 



1 0.3 
' X- 



B 



where k^ is Terzaghi's modulus of subgrade reaction 
as determined from load deflection measurements on 
a 30 cm square plate and B is the width of the pile 
(diameter in case of circular piles). The recommended 
values of k^ are given in Table 4. 

Table 4 Modulus of Subgrade Reaction for 
Cohesive Soil, k^ in kN/m^ 



Si 


Soil 




Unconfined 


Range of k^ 


No. 


Consistency 


Compression 


kN/m' X 10' 








Strength, q^ 










kN/m^ 




(1) 


(2) 




(3) 


(4) 


i) 


Soft 




25-50 


4.5-9.0 


ii) 


Medium stiff 


50-100 


9.0-18.0 


iii) 


Stiff 




100-200 


18.0-36.0 


iv) 


Very stiff 




200-400 


36.0-72.0 


V) 


Hard 




> 400 


>72.0 


NOTE — For 


q^ less than 25, i, may 


be taken as zero, 


which implies 


that 


there is no lateral 


resistance. 



12 



IS 2911 (Part 1/Sec 1) : 2010 



C-2.3 Stiffness Factors 

C-2.3.1 For Piles in Sand and Normally Loaded 
Clays 



Stiffness factor T, in m : 



where 

E = Young's modulus of pile material, in 

MNIm-; 

I = moment of inertia of the pile cross- 
section, in m"*; and 

Tji^ = modulus of subgrade reaction, in MN/m^ 
{see Table 3). 

C-2.3.2 For Piles in Preloaded Clays 



Stiffness factor /?, in m = 4 |_^ 

KB 



where 



E = Young's modulus of pile material, in 

MN/m^; 

/ = moment of inertia of the pile cross- 
section, in m"*; 

k 3 
K = YT ^ ~ir (^^^ Table 4 for values of k , in 
1.5 B 

MN/m^); and 

B = width of pile shaft (diameter in case of 
circular piles), in m. 



C-3 CRITERIA FOR SHORT RIGID PILES 
AND LONG ELASTIC PILES 

Having calculated the stiffness factor T or R, the 
criteria for behaviour as a short rigid pile or as a long 
elastic pile are related to the embedded length L as 
given in Table 5. 

Table 5 Criteria for Behaviour of Pile 
Based on its Embedded Length 



SI 


Type of Pile 


Relation of Embedded 


No. 


Behaviour 


Length with 
Stiffness Factor 

A 




Linearly Constant 






Increasing 


(1) 


(2) 


(3) (4) 



i) Short (rigid) pile L < 2T L < 2R 

ii) Long (elastic) pile L > 4T L > 3.5R 

NOTE — The intermediate L shall indicate a case 
between rigid pile behaviour and elastic pile 
behaviour. 

C-4 DEFLECTION AND MOMENTS IN 
LONG ELASTIC PILES 

C-4.1 Equivalent cantilever approach gives a simple 
procedure for obtaining the deflections and moments 
due to relatively small lateral loads. This requires 
the determination of depth of virtual fixity, z^ 

The depth to the point of fixity may be read from 
the plots given in Fig. 3. e is the effective 
eccentricity of the point of load application obtained 
either by converting the moment to an equivalent 
horizontal load or by actual position of the 
horizontal load application. R and T are the stiffness 
factors described earlier. 



^ I 




"I 



V -^ 



1 POff PILES IN SN-B& AND 

r I 






FRiE HSAD PILES 

__ ^ _ FIXED HE*D PILES 



HbRMflLLV LDAfl^ti CLAYS 



K^fl PUfS IN nSLQAEED 



Fig. 3 Depth of Fixity 
13 



IS 2911 (Part 1/Sec 1) : 2010 

C-4.2 The pile head deflection, y shall be computed 
using the following equations: 

Deflection, y = ^^Itf^^ x 10^ 



3EI 



.for free head pile 



Deflection, y = ^^^^^i' x 10^ 

...for fixed head pile 
where 

H = lateral load, in kN; 

y = deflection of pile head, in mm; 

E = Young's modulus of pile material, in 

kN/m^; 
/ = moment of inertia of the pile cross-section, 

in m*; 
Zj = depth to point of fixity, in m; and 
e = cantilever length above ground/bed to the 

point of load application, in m. 



C-4.3 The fixed end moment of the pile for the 
equivalent cantilever may be determined from the 
following expressions: 

Fixed end moment, M^ =H{e + Zf) 

. . .for free head pile 

Hje + Zt) 
2 

...for fixed head pile 

The fixed end moment, M^ of the equivalent 
cantilever is higher than the actual maximum 
moment M in the pile. The actual maximum moment 
may be obtained by multiplying the fixed end 
moment of the equivalent cantilever by a reduction 
factor, m, given in Fig. 4. 



Fixed end moment, M_ = 

' F 



B 

^ 






ija 



3 8 



q£ 



OA 



lif'm [Mr ^ 



^2 









^^^ 


"" 


■■ 


■f- 


^0 ^ 


1 , 






J-1 

v: 


7-7- 








F 







ID } '4 4 4 V 1= 

F0R«>LESINPfl£:.OABE[>ClAYS 

FOR PILES A|S*^ND&ANt> 
WQHMA1J.Y LC*OE& CtA¥3 

4A For Free Head Pile 







FOR PILES IN PRElOAOEU CmTS 



FOR PILES IH SAMDB AhC 

NOPHfeJLlf LOWED cmva 

4B For Fixed Head Pile 
Fig. 4 Determination of Reduction Factors for Computation of Maximum Moment in Pile 



14 



IS 2911 (Part 1/Sec 1) : 2010 



ANNEX D 
(Clause 8.7.2) 

DATA SHEET 

Site 

Title 

Date of enquiry 

Date piling commenced 

Actual or anticipated date for completion of piling work 

Number of pile 



TEST PILE DATA 



Pile: 



Pile type: 



Pile test commenced . 
Pile test completed ... 



Pile specification: 



Sequence of piling: 
(for groups) 



(Mention proprietary system, if any) . 
I Shape — Round/Square 

Size — Shaft 

Reinforcement No 



.Tip. 



. dia for (depth) 



From centre towards the periphery or from periphery towards the centre 



Concrete : 



Weight of hammer 



Fall of hammer 

No. of blows during last 25 mm of driving 

Dynamic formula used, if any 

Calculated value of working load 



Mix ratio 1: by volume/weight 

or strength after days N/mm^ 

Quantity of cement/m^: 

Extra cement added, if any: 

Type of hammer 

(Specify rated energy, if any) 

Length finally driven 



Test loading: 

Maintained load/Cyclic loading/C.R.P. 



(Calculations may be included) 



15 



IS 2911 (Part 1/Sec 1) : 2010 

Capacity of jack 

If anchor piles used, give No., Length 

Distance of test pile from nearest anchor pile 

Test pile and anchor piles were/were not working piles 
Method of Taking Observations: 

Dial gauges/Engineers level 

Reduced level of pile tip 

General Remarks: 



Special Difficulties Encountered: 



Results: 

Working load specified for the test pile 

Settlement specified for the test pile 

Settlement specified for the structure 

Working load accepted for a single pile as a result of the test . 



Working load in a group of piles accepted as a result of the test . 



General description of the structure to be founded on piles 



Name of the piling agency . 



16 



IS 2911 (Part 1/Sec 1) : 2010 

Name of person conducting the test 

Name of the party for whom the test was conducted 

BORE-HOLE LOG 

1. Site of bore hole relative to test pile position 

2. If no bore hole, give best available ground conditions 



Soil Soil Reduced Soil Depth Thickness 

Properties Description Level Legend below Ground Level of Strata 



Position of the 

tip of pile to 

be indicated thus- 



Standing ground 
Water level indicated 

thusY7 



METHOD OF SITE INVESTIGATION 

Trial pit/Post-hole auger/Shell and auger boring/Percussion/Probing/Wash borings/Mud-rotary drilling/ 
Core-drilling/Shot drilling/Sub-surface sounding by cones or Standard sampler 



NOTE — Graphs, showing the following relations, shall be prepared and added to the report: 

a) Load vs Time, and 

b) Settlement vs Load. 



17 



IS 2911 (Part 1/Sec 1) : 2010 



ANNEX E 

(Foreword) 

COMMITTEE COMPOSITION 

Soil and Foundation Engineering Sectional Committee, CED 43 



Organization 

In personal capacity (188/90, Prince Anwar Shah Road, 
Kolkatta 700045) 

A. P. Engineering Research Laboratories, Hyderabad 

AFCONS Infrastructure Limited, Mumbai 

Central Board of Irrigation & Power, New Delhi 
Central Building Research Institute, Roorkee 

Central Electricity Authority. New Delhi 

Central Public Works Department, New Delhi 

Central Road Research Institute, New Delhi 

Central Soil & Materials Research Station, New Delhi 

Engineer-in-Chief's Branch, New Delhi 

Engineers India Limited, New Delhi 

F. S. Engineers Pvt Limited, Chennai 
Gammon India Limited, Mumbai 

Ground Engineering Limited, New Delhi 

Gujarat Engineering Research Institute, Vadodara 

Indian Geotechnical Society, New Delhi 

Indian Institute of Science, Bangalore 

Indian Institute of Technology, Chennai 

Indian Institute of Technology, New Delhi 

Indian Institute of Technology, Mumbai 
Indian Institute of Technology, Roorkee 

Indian Society of Earthquake Technology, Uttaranchal 
ITD Cementation India Ltd. Kolkata 

M.N. Dastur & Coinpany (P) Ltd, Kolkata 

M/s Cengrs Geotechnical Pvt Limited, New Delhi 

Ministry of Surface Transport, New Delhi 

Mumbai Port Trust, Mumbai 

Nagadi Consultants Pvt Limited, New Delhi 

National Thermal Power Corporation Limited, Noida 



Representative(s) 
Dr N. Som (Chairman) 

Shri p. Sivakantham 

Shri p. John Victor (Alternate) 

Shri A. D. Londhe 

Shri V. S. Kulkarni (Alternate) 

Director 

Shri Y. Pandey 

Shri R. Dharmraju (Alternate) 

Director (TCD) 

Deputy Director (TCD) (Alternate) 

Superintending Engineer (Design) 

Executive Engineer (Design-V) (Alternate) 

Shri Sudhir Mathur 

Shri Vasant G. Havangi (Alternate) 

Shri S. K. Babbar 

Shri D. N. Bera (Alternate) 

Shri J. B. Sharma 

Shri N. K. Jain (Alternate) 

Shri T. Balrai 

Shri S. Debnath (Alternate) 

Dr a. Verghese Chummar 

Dr N. V. Nayak 

Shri S. Pattiwar (Alternate) 

Shri Ashok Kumar Jain 

Shri Neerai Kumar Jain (Alternate) 

Director 

Shri J. K. Patel (Alternate) 

Secretary 

Prof A. Sridharan 

Prof S. R. Ghandi 

Dr a. Varadaraian 

Dr R. Kaniraj (Alternate) 

Shri G. Venkatachalam 

Prof M. N. Viladkar 

Dr Mahendra Singh (Alternate) 

Representative 

Shri P. S. Sengupta 

Shri Manish Kumar (Alternate) 

Director-Civil Structural 

Shri S. N. Pal (Alternate) 

Shri Saniay Gupta 

Shri Ravi Sundaram (Alternate) 

Shri A. K. Banerjee 

Shri Satish Kumar (Alternate) 

Shrimati R. S. Hardikar 

Shri A. J. Lokhande (Alternate) 

Dr V. V. S. Rao 

Shri N. Santosh Rao (Alternate) 

Dr D. N. Naresh 

Shri B. V. R. Sharma (Alternate) 



18 



IS 2911 (Part 1/Sec 1) : 2010 



Organization 

Pile Foundation Constructions Co (I) Pvt Limited, 
Kolkata 

Safe Enterprises, Mumbai 

School of Planning and Architecture, New Delhi 
Simplex Infrastructures Limited, Chennai 

The Pressure Piling Co (I) Pvt Limited. Mumbai 

University of Jodhpur, Jodhpur 
BIS Directorate General 



Representative(s) 

Shri B. p. Guha NlYOGl 

Shri S. Bhowmik (Alternate) 

Shri Vikram Singh Rao 

Shri Suryaveer Singh Rao (Alternate) 

Proe V. Thirivengadam 

Shri Shankar Guha 

Shri S. Ray (Alternate) 

Shri V. C. Deshpande 

Shri Pushkar V. Deshpande (Alternate) 

Shri G. R. Chowdhary 

Shri A. K. Saini, Scientist 'F' & Head (CED) 
[Representing Director General (Ex-ojficio)} 



Member Secretary 

Shrimati Madhurima Madhav 

Scientist 'B' (CED), BIS 

Pile and Deep Foundations Subcommittee, CED 43 : 5 



In personal capacity (Satya Avenue, 2nd Cross Street, 
Janganatha Puram, Velachery, Chennai 600042) 

AFCONS Infrastructure Ltd, Mumbai 

Association of Piling Specialists (India), Mumbai 

Central Building Research Institute, Roorkee 

Central Public Works Department, New Delhi 

Engineer-in-Chief's Branch, New Delhi 
Engineers India Limited, New Delhi 

Gammon India Limited, Mumbai 

Ground Engineering Limited, New Delhi 

Indian Geotechnical Society, New Delhi 

Indian Institute of Technology, Chennai 

Indian Institute of Technology, Roorkee 
Indian Roads Congress, New Delhi 

ITD Cementation India Limited, Kolkata 

M/s Cengrs Geotechnical Pvt Limited, New Delhi 

Ministry of Shipping, Road Transport and Highways, 
New Delhi 

National Thermal Power Corporation, Noida 

Pile Foundation Constructions Co (I) Pvt Limited, 
Kolkata 

Research, Designs & Standards Organization, Lucknow 
Simplex Infrastructures Limited, Chennai 
Structural Engineering Research Centre, Chennai 
TCE Consulting Engineers Limited, Mumbai 
Victoria-Jubilee Technical Institute, Mumbai 



Shri Murli Iyengar (Convener) 

Shri A. N. Jangle 

Shri V. T. Ganpule 

Shri Madhukar Lodhavia (Alternate) 

Shri R. Dharamraju 

Shri A. K. Sharma (Alternate) 

Superintending Engineer (Design) 

Executive Engineer (Design Division V) (Alternate) 

Director General oe Works 

Dr Atul Nanda 

Shri Sanjay Kumar (Alternate) 

Dr N. V. Nayak 

Shri R. K. Malhotra (Alternate) 

Shri Ashok Kumar Jain 

Shri Neeraj Kumar Jain (Alternate) 

Dr Satyendra Mittal 

Dr K. Rajagopal (Alternate) 

Dr S. R. Gandhi 

Dr a. Bhoominathan (Alternate) 

Dr G. Ramasamy 

Shri A. K. Baneriee 

Shri I. K. Pandey (Alternate) 
Shri Manish Kumar 

Shri Partho S. Sengupta (Alternate) 
Shri Sanjay Gupta 

Shri Ravi Sunduram (Alternate) 
Shri V. K. Sinha 

Shri R. R. Maurya 

Shri V. V. S. Ramdas (Alternate) 

Shri B. P. Guha Niyogi 

Shri S. Bhowmik (Alternate) 

Director (B&S) 

Director GE (Alternate) 
Shri Shankar Guha 

Shri S. Ray (Alternate) 
Shri N. Gopalakrishnan 

Dr K. Ramanjaneyulu (Alternate) 
Shri C. K. Ravindranathan 

Shri S. M. Palerkar (Alternate) 
Representative 



19 



Bureau of Indian Standards 

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote 
harmonious development of the activities of standardization, marking and quality certification of goods 
and attending to connected matters in the country. 

Copyright 

BIS has the copyright of all its publications. No part of these publications may be reproduced in any form 
without the prior permission in writing of BIS. This does not preclude the free use, in the course of 
implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. 
Enquiries relating to copyright be addressed to the Director (Publications), BIS. 

Review of Indian Standards 

Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed 
periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are 
needed; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standards 
should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue 
of 'BIS Catalogue' and 'Standards : Monthly Additions'. 

This Indian Standard has been developed from Doc No.: CED 43 (7282). 

Amendments Issued Since Publication 

Amend No. Date of Issue Text Affected 



BUREAU OF INDIAN STANDARDS 
Headquarters: 

Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002 

Telephones: 2323 0131, 2323 3375, 2323 9402 Website: www.bis.org.in 

Regional Offices: Telephones 

Central : Manak Bhavan, 9 Bahadur Shah Zafar Marg j 2323 7617 

NEW DELHI 110002 12323 3841 

Eastern : 1/14 C. I. T. Scheme VI M, V. I. P. Road, Kankurgachi [2337 4899, 2337 8561 

KOLKATA 700054 12337 8626,2337 9120 

Northern : SCO 335-336, Sector 34-A, CHANDIGARH 160022 ; 260 3843 

I 260 9285 

Southern : C. I. T Campus, IV Cross Road, CHENNAI 600113 f 2254 1216, 2254 1442 

12254 2519, 2254 2315 

Western : Manakalaya, E9 MIDC, Marol, Andheri (East) f 2832 9295, 2832 7858 

MUMBAI 400093 I 2832 7891, 2832 7892 

Branches: AHMEDABAD. BANGALORE. BHOPAL. BHUBANESHWAR. COIMBATORE. DEHRADUN. 
FARIDABAD. GHAZIABAD. GUWAHAH. HYDERABAD. JAIPUR. KANPUR. LUCKNOW NAGPUR. 
PARWANOO. PATNA. PUNE. RAJKOT THIRUVANANTHAPURAM. VISAKHAPATNAM. 



Typeset by : S.S. Computers, Delhi